Assertions Questions and Answers

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Showing 10 of 45 questions
Q1
 What will be the output of the program? public class Test {      public static void main(String[] args)     {         int x = 0;          assert (x > 0) ? "assertion failed" : "assertion passed" ;         System.out.println("finished");      } }
  • A finished
  • B Compiliation fails.
  • C An AssertionError is thrown and finished is output.
  • D An AssertionError is thrown with the message "assertion failed."
Answer: Option B
Q2
public class Test {     public void foo()     {         assert false; /* Line 5 */         assert false; /* Line 6 */     }     public void bar()     {         while(true)         {             assert false; /* Line 12 */         }         assert false;  /* Line 14 */     } } What causes compilation to fail?
  • A Line 5
  • B Line 6
  • C Line 12
  • D Line 14
Answer: Option D
Q3
What will be the output of the program? public class Test {     public static int y;     public static void foo(int x)     {         System.out.print("foo ");         y = x;     }     public static int bar(int z)     {         System.out.print("bar ");         return y = z;     }     public static void main(String [] args )     {         int t = 0;         assert t > 0 : bar(7);         assert t > 1 : foo(8); /* Line 18 */         System.out.println("done ");     } }
  • A bar
  • B bar done
  • C foo done
  • D Compilation fails
Answer: Option D
Q4
What will be the output of the program (when you run with the -ea option) ? public class Test {      public static void main(String[] args)     {         int x = 0;          assert (x > 0) : "assertion failed"; /* Line 6 */         System.out.println("finished");     } }
  • A finished
  • B Compilation fails.
  • C An AssertionError is thrown.
  • D An AssertionError is thrown and finished is output.
Answer: Option C
Q5
public class Test2 {     public static int x;     public static int foo(int y)     {         return y * 2;     }     public static void main(String [] args)     {         int z = 5;         assert z > 0; /* Line 11 */         assert z > 2: foo(z); /* Line 12 */         if ( z < 7 )             assert z > 4; /* Line 14 */         switch (z)         {             case 4: System.out.println("4 ");             case 5: System.out.println("5 ");             default: assert z < 10;         }         if ( z < 10 )             assert z > 4: z++; /* Line 22 */         System.out.println(z);     } } which line is an example of an inappropriate use of assertions?
  • A Line 11
  • B Line 12
  • C Line 14
  • D Line 22
Answer: Option D
Q6
What is the primary purpose of assertions in Java?
  • A To handle runtime exceptions
  • B To improve code performance
  • C To validate assumptions during development
  • D To replace exception handling
Answer: Option C
Explanation: Assertions are used for debugging and testing during development to verify assumptions about program state.
Q7
Which keyword is used to declare an assertion in Java?
  • A assertion
  • B assert
  • C Assert
  • D validate
Answer: Option B
Explanation: The assert keyword is used for assertions in Java.
Q8
What happens by default when an assertion fails at runtime?
  • A Compilation error occurs
  • B AssertionError is thrown
  • C NullPointerException is thrown
  • D Program continues execution silently
Answer: Option B
Explanation: A failed assertion throws AssertionError, which is not typically caught.
Q9
How are assertions enabled at runtime?
  • A Using -enableassertions or -ea
  • B Using -enableassertions=true in code
  • C They are always enabled by default
  • D Using @EnableAssertions annotation
Answer: Option A
Explanation: Assertions are disabled by default and must be explicitly enabled using -ea flag.
Q10
Which of the following is the correct syntax for assert statement?
  • A assert condition;
  • B assert(condition);
  • C Assert condition;
  • D assert condition : message;
Answer: Option A
Explanation: Assert can have simple boolean expression or boolean expression with message.
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